Currently, melt furnaces for automatic casting have been heard of where the liquid metal is heated in the tank by means of inducers placed on the base or on the sides or by means of plasma as in the EP0916435.
The melt from the runner must be strictly adjusted to the manufacturing order, which depends on the nature of the part to be melted.
This nature means that the metal in the runner must be at a pre-established and variable temperature(xcex8) for each type of part, admitting small margins (xcex8+xcex94) in the temperature variations with respect to the pre-established temperature, these margins also varying for each part to be melted.
As a result, and within the rate of the manufacturing orders, the temperature (xcex8) in the runner must vary and therefore, the temperature of the liquid metal in the runner is made to vary, which gives rise, due to its great mass, to great inertias, little flexibility and great energy expenditure.
The applicant has solved the aforementioned problem creating an additional chamber between the tank and the runner and arranging for the heating of this additional chamber to be by plasma.
This arrangement means that when the temperature (xcex8) of the liquid metal in the runner has to be increased due to needs of the part to be cast or others, the mass of the liquid metal to be heated is small (only the additional chamber mass) and thanks to the plasma, the heating is practically instantaneous, with which the flexibility of the system increases enormously, adapting immediately to the needs, representing a great energy saving.
To improve the furnace even more the invention foresees that the additional chamber will have connection downstream from the runner, that is, towards the nozzle outlet of the storage tank.
This additional chamber means that the current heating means of the tank such as the inducer or plasma are unnecessary, although it can perfectly be added to them.
It will be understood that if the heating means of the tank are removed, the volume (V) of the additional chamber will be greater than if it is decided to maintain them and use them when desired, in the first case, the volume (V) of the additional chamber being able to be between 5 and 10% of the total working volume (Vt) of the furnace: 5% Vtxe2x89xa6Vxe2x89xa610% Vt, and in the second case between 15 and 20%, that is, 15% Vtxe2x89xa6Vxe2x89xa620% Vt, these amounts being approximate and experimental.